1. Field of the Invention
This invention relates to a switch device for driving a plurality of switch elements by pressing an actuator at a plurality of positions in the surface thereof and, more particularly, to a waterproof structure for the switch device.
2. Description of the Prior Art
A switch device shown, for example, in FIGS. 3 and 4 is heretofore known as a switch for driving a mirror provided in a vehicle by an electric motor.
In the drawings, reference numeral 1 denotes an upper case opened at its lower end, and numeral 2 denotes a lower case for closing the open end of the upper case 1, and both cases 1 and 2 are snap-coupled to form the outer sheath of the switch device. A printed substrate 3 is placed on the lower case 2, and four lever switches 4 and a slide switch 5 are soldered to the printed substrate 3. The lever switch 4 is known to change over the switch by turning a lever 4b by pressing an L-shaped actuator 4a projected from the upper end thereof, and the slide switch 5 is known to change over the switch by sliding the operation lever 5a projected from the upper end thereof.
A square stepped portions 6 and a flat-shaped track-like recess 7 are formed in parallel on the upper surface of the upper case 1. Operation openings 8 are perforated corresponding to the lever switches 4 at four corners of the stepped portion 6, and a projecting wall 10 having a through opening 9 is formed at the center of the stepped portion 6. An operation opening 11 is perforated along the longitudinal direction on the bottom of the recess 7.
Reference numeral 12 denotes a square actuator of plane shape, long pressing projections 12a are suspended down from four corners of the lower surface of the actuator 12, short projections 12b are suspended down from the intermediate positions of the pressing projections 12a, and further suspended with latch pawls 12c of the actuator 12. The actuator 12 thus formed is inserted into the stepped portion 6 with conical rubber pressing buttons 13 interposed between the bottom of the stepped portion 6 and the projections 12b, and the latch pawls 12c are latched with the lower peripheral edges of the projecting wall 10 to prevent it from being removed. Therefore, when the corner of the actuator 12 is pressed against the elastic tension of the rubber pressing button 13, the pressing projection 12a opposed to the lever switch 4 is moved down through the operation opening 8 to press the actuator, thereby selectively turning ON the lever switches 4.
Reference numeral 14 denotes an operation knob. An operation shaft 14a suspended from the operation knob 14 is inserted into the operation opening 11 to be engaged with the operation lever 5a of the slide switch 5. Thus, when the operation knob 14 is moved along the longitudinal direction of the recess 7, the operation lever 5a reciprocates in cooperation therewith to switch the slide switch 5.
Next, the operation of the switch device constructed as described above will be described
When the operation knob 14 is reciprocated along the operation opening 11 as described above, the slide switch 5 is switched to select, for example, any of right and left mirrors. When the corner of the actuator 12 is depressed, the actuator 12 is tilted in the pressed direction, the pressing projection 12a of the position pressed as described above is moved down to turn ON the opposed lever switch 4. In this case, since the rubber pressing button 13 is deformed by the depression of the actuator 12, an operator can recognize the switching operation of the lever switch 4 as click feeling (knock feeling). When the pressing force is released, the actuator 12 is returned by the recoiling strength of the rubber pressing button 13 to the state as shown in FIG. 3. Therefore, one of four lever switches 4 is selectively turned ON by selecting the pressing position of the actuator 12 so that an electric motor, not shown, is started to transmit the driving force through a power transmission system, not shown, to the mirror of the side selected by the operation knob 14, thereby driving (tilting) the mirror in the pressing direction of the actuator 12.
In the switch device constructed as described above, the pressing projection 12a suspended down from the actuator 12 moves elevationally in the operation opening 8 perforated at the upper case 1 to operate the switch element (lever switch 4). Thus, when liquid such as rainy water or drinking water is splashed over the switch device, the liquid is introduced into the upper case 11 through a gap formed between the upper end opening of the stepped portion 6 and the peripheral edge of the actuator 12. When the liquid is thus introduced into the upper case 1, there arises a problem that the wiring patterns of the printed substrate 3 or the contacts of the switch elements are shorted to cause a serious defect in the switch device.